Embodiments of the invention relate generally to the field of prognostics of blades or airfoils, and more specifically to methods and systems for determination of health of blades.
Rotor blades or airfoils are used in several devices, for example, axial compressors, turbines, engines, turbomachines, or the like. An axial compressor has a series of stages with each stage comprising a row of rotor blades or airfoils followed by a row of static blades or static airfoils. Accordingly, each stage comprises a pair of rotor blades or airfoils and static airfoils. In an axial compressor, the rotor blades increase the kinetic energy of a fluid that enters the axial compressor through an inlet. Furthermore, the static blades generally convert the increased kinetic energy of the fluid into static pressure through diffusion. Accordingly, the rotor blades and static blades play an important role to increase the pressure of the fluid.
Furthermore, the rotor blades or airfoils and the static airfoils are vital due to wide and varied applications of the axial compressors that include the airfoils. Axial compressors, for example, may be used in a number of devices, such as, land based gas turbines, jet engines, high speed ship engines, small scale power stations, or the like. In addition, the axial compressors may be used in other applications, such as, large volume air separation plants, blast furnace air, fluid catalytic cracking air, propane dehydrogenation, or the like.
The blades or airfoils operate for long hours under extreme and varied operating conditions, such as, high speed, fluid load, and temperature that affect the health of the airfoils. In addition to the extreme and varied conditions, certain other factors lead to fatigue and stress on the airfoils. The factors, for example, may include centrifugal forces, fluid forces, thermal loads during transient events, load due to non-synchronous vibration, such as, rotating stall, and the cyclic load due to synchronous resonant vibration. Prolonged effects of the factors lead to defects, such as, tip loss, or deflection in the airfoils.
Accordingly, it is highly desirable to develop a system and method that may predict health of airfoils in real time. More particularly, it is desirable to develop a system and method that may predict cracks or fractures in real time.